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Utilization of desktop 3D printer-fabricated "Cost-Effective" 3D models in orthognathic surgery
Narita, Masato,Takaki, Takashi,Shibahara, Takahiko,Iwamoto, Masashi,Yakushiji, Takashi,Kamio, Takashi Korean Association of Maxillofacial Plastic and Re 2020 Maxillofacial Plastic Reconstructive Surgery Vol.42 No.-
Background: In daily practice, three-dimensional patient-specific jawbone models (3D models) are a useful tool in surgical planning and simulation, resident training, patient education, and communication between the physicians in charge. The progressive improvements of the hardware and software have made it easy to obtain 3D models. Recently, in the field of oral and maxillofacial surgery, there are many reports on the benefits of 3D models. We introduced a desktop 3D printer in our department, and after a prolonged struggle, we successfully constructed an environment for the "in-house" fabrication of the previously outsourced 3D models that were initially outsourced. Through various efforts, it is now possible to supply inexpensive 3D models stably, and thus ensure safety and precision in surgeries. We report the cases in which inexpensive 3D models were used for orthodontic surgical simulation and discuss the surgical outcomes. Review: We explained the specific CT scanning considerations for 3D printing, 3D printing failures, and how to deal with them. We also used 3D models fabricated in our system to determine the contribution to the surgery. Based on the surgical outcomes of the two operators, we compared the operating time and the amount of bleeding for 25 patients who underwent surgery using a 3D model in preoperative simulations and 20 patients without using a 3D model. There was a statistically significant difference in the operating time between the two groups. Conclusions: In this article, we present, with surgical examples, our in-house practice of 3D simulation at low costs, the reality of 3D model fabrication, problems to be resolved, and some future prospects.
Masanao Obayashi,Kenichiro Narita,Takashi Kuremoto,Kunikazu Kobayashi 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
Human learns incidents by own actions and reflects them on the subsequent action as own experiences. These experiences are memorized in his brain and recollected if necessary. This research incorporates such an intelligent information processing mechanism, and applies it to an autonomous agent that has three main functions: learning, memorization and associative recollection. In the proposed system, an actor-critic type reinforcement learning method is used for learning. Auto-associative chaotic neural network is also used like mutual associative memory system. Moreover, the memory part has an adaptive hierarchical layered structure of the memory module that consists of chaotic neural networks in consideration of the adjustment to non-MDP (Markov Decision Process) environment. Finally, the effectiveness of this proposed method is verified through the simulation applied to the maze-searching problem.
Iwamoto, Masashi,Watanabe, Miki,Yamamoto, Masae,Narita, Masato,Kamio, Takashi,Takaki, Takashi,Shibahara, Takahiko,Katakura, Akira Korean Association of Maxillofacial Plastic and Re 2019 Maxillofacial Plastic Reconstructive Surgery Vol.41 No.-
Background: Le Fort I osteotomy is one of the surgical procedures now routinely and safely performed. It is possible to move the maxilla in three dimensions, but it is necessary to separate the bones around the maxillary sinus. Therefore, with surgery, maxillary sinus mucosal thickening occurs. By knowing the changes in the sinus mucosa after surgery and the factors affecting it, it is possible to better predict the outcomes of surgery and contribute to safer surgery. In this study, thickening of maxillary sinus mucosa before and after surgery in Le Fort I osteotomy was evaluated using multidetector-row computed tomography (MDCT) images, and the changes in mucosal thickening and the related factors were examined. Methods: Using MDCT images, the maxillary sinus mucosa of 125 patients who had undergone Le Fort I osteotomy was retrospectively evaluated before surgery, 1 month after surgery, and 1 year after surgery. On the MDCT images, the maxillary sinus was judged as mucosal thickening and classified into three grades according to the proportion occupying the maxillary sinus. In the evaluation of factors related to mucosal thickening, the following eight factors were examined: sex, age, diagnosis, operating time, amount of postoperative bleeding, with/without bone graft, with/without multisegmental osteotomy, and with/without macrolide therapy after surgery. Results: The mean age at the time of surgery was 25.6 ± 8 years. Of all 125 patients, 66 had bilateral thickening, 19 had unilateral thickening, and 40 had no thickening. Factors that were significantly related to mucosal thickening were the operative time for the maxilla, bone grafts, and macrolide therapy after surgery. Conclusions: Operative time for the maxilla, bone grafts, and macrolide therapy after surgery were found to be related to mucosal thickening. In addition, MDCT scanning 1 month after surgery was considered to be appropriate for evaluation of maxillary sinus mucosal thickening.
Enomoto Keigo,Eguchi Yawara,Sato Takashi,Norimoto Masaki,Inoue Masahiro,Watanabe Atsuya,Sakai Takayuki,Yoneyama Masami,Aoki Yasuchika,Orita Sumihisa,Narita Miyako,Inage Kazuhide,Shiga Yasuhiro,Umimura 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.1
Study Design: Retrospective observational study.Purpose: We investigated the correlation between T2 relaxation times and clinical symptoms in patients with cervical radiculopathy caused by cervical disk herniation.Overview of Literature: There are currently no imaging modalities that can assess the affected cervical nerve roots quantitatively.Methods: A total of 14 patients with unilateral radicular symptoms and five healthy subjects were subjected to simultaneous apparent T2 mapping and neurography with nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement signaling (SHINKEI-Quant) using a 3-Tesla magnetic resonance imaging. The Visual Analog Scale (VAS) score for neck pain and upper arm pain was used to evaluate clinical symptoms. T2 relaxation times of the cervical dorsal root ganglia of the brachial plexus were measured bilaterally from C4 to C8 in patients with radicular symptoms and from C5 to C8 in healthy controls. The T2 ratio was calculated as the affected side to unaffected side.Results: When comparing nerve roots bilaterally at each spinal level, no significant differences in T2 relaxation times were found between patients and healthy subjects. However, T2 relaxation times of nerve roots in the patients with unilateral radicular symptoms were significantly prolonged on the involved side compared with the uninvolved side (p<0.05). The VAS score for upper arm pain was not significantly correlated with the T2 relaxation times, but was positively correlated with the T2 ratio.Conclusions: In patients with cervical radiculopathy, the SHINKEI-Quant technique can be used to quantitatively evaluate the compressed cervical nerve roots. The VAS score for upper arm pain was positively correlated with the T2 ratio. This suggests that the SHINKEI-Quant is a potential tool for the diagnosis of cervical nerve entrapment.